In a number of applications, such as in food handling and other circumstances where cleanliness of equipment is important, it is desirable to build caster wheels in such a way that the tire and hub when assembled together, form a relatively recess-free surface which is easy to clean. This objective is normally accomplished by providing a hollow wheel of generally rectangular cross-section whose width is generally equal to the width of the tire which is vulcanized onto the rolling surface of the wheel. In the highly competitive caster industry, it is imperative to manufacture a caster conforming to these requirements at the least possible cost.
Currently, two principal ways of manufacturing a wheel of this type are in use: stamping followed by press-fitting (which is undesirable because the press-fit tends to work loose in use), and stamping followed by welding. In the first method, two generally symmetrical halves of the wheel are stamped from flat stock by a series of successive stamping operations, and then press-fitted together. In the second method, two identical stampings forming the two havles of the outer portion of the wheel, and a sleeve forming the hub portion of the wheel, are all welded together to form a unitary hollow wheel. In either method, a subsequent plating operation is often necessary to produce an estehtically acceptable wheel body surface.
In view of the need for cost-effective manufacture of high-quality caster wheels for the above-mentioned applications, it has therefore become necessary to devise a wheel body structure of the type described which lends itself to easy assembly in a single step without further processing, yet provides a sturdy, well-sealed hollow wheel body.